Sealing and leveling means for lifter roof tanks



Feb. 21, 1950 E. s. FRASER 2,497,878

SEALING AND LEVELING MEANS FOR LIFTER ROOF TANKS.

Filed May 31, 1946 H 2 Sheets-Sheet 1 1920677302": Jdwemd JJWaaenPatented Feb. 21, 1950 UNITED STAT ES PATENT F FICE wists r SEALING ANbnEvELiNG MEANS FOR 1F F TAN SS,. 3'. Edward S. Erasen,ChicagmIlL,"assignor to Ghi ca-go Bridge & Iron Company, a corporation-of l noiApplication This invention relates to'a lifter roof tank comprising ashell and" a lifter roof thereove'r; "and relates particularly to asealing and leveling meanssfor such a tank Y Lifter roof tanks aredesigned lfDI the storage of gas and mixturesof liquid and gas. nthesetanks theroof rises and falls 'as' thepre'ssui'e bf gas withinthe tankis increased and decreased. It is necessary that arsealing means beprovided to 'seal 'the area betweentl ie roof and the she'll 6f the tankand that stabilizing and leveling-' means also be providedtomaintain'the roof substantially level at all times." In thepresent-invention the sealing and-"leveling ine'an's'haVe been combinedso asto produce a simpler and more satisfactory construction;

The present invention broadly comprises a trough of substantial depth atthe top of the shell, 2. depending hollow compartment attached tothereof and extending into the trough, and'a lid'uid substantiallyfilling the trough when the roof is in its lowest po'siti'on, with'thecompartment being im-me'rsedin the liquid.

'The invention will be described as related to the embodiments shown inthe accompanying drawings. Of the drawings,- Fig. 1- is a frag;- mentaryplan view of a lifter roof tank embodying the invention i Fig. 2 is avertical section taken along line 2- -2 of Fig. 1; Fig. 3 is a verticalsection similar to Fig; 2" showing an alternate embodiment of theinvention; Fig. 4 is a'view similar to Fig. 2 showing another embodimentof the invention; Fig. 5 is a view similar to- Fig. 2 showing stillanother embodiment of the invention; and Fig. 6 is a view similar toFig. 2 another embodiment-01f the invention.

In the embodiments shown 'inthe accompanying drawings the lifter rooftank comprises a shell H), a lifter roof Ii thereover having a dependingskirt [2 attached to the edge of the lifter roof H beyond the shell It.In the embodiment shown in Figs. 1 and 2 there is provided a trough 13at the top of the shell supported on brackets 14 and havingsubstantially parallel sides l5. Inner i5 and outer i 1 angle irons areprovided at the top of the trough in order to give the sides stability.A depending hollow compartment I8 is attached to the roof and extendsdown into the trough I3. This compartment may be continuous around theroof, or may be made in sections divided by transverse bulkheads. Aliquid I9 is provided within the trough I3 and substantially fills thetrough when the roof is in its lowest position as shown in Fig. 2. Thehollow compartment I 8 is fluid-tight for at least that portion s s nMayBl, 194G, Sel'ialNo. 673,676

8 Claims. (Cl. 48-176) which isimmersedfin the liquid. Thecompartmentmay, however; have an opening to I the atmosphere-at a point:above. the liquid level. There is also provi'de'da drip bar-2!] onthebottom surface of the lifter roof l2, with this drip loar beinglocated-inwardly'from: the trough l5 so thatvapors condensing on thebottom surface ofthe roof will not fall'into th trough, but will'dripback into the shell of the tank: There is also. provided an angle iron2! around the bottom of the skirt I! in order to givetlieskirt"rigidity;

The compartment 1 8 and: the liquid l:9-provide a seal to prevent theescape of vapors from-.ivithin thetank; The compartment will also resistany tendency of the roof to" leave aa'horiz'o'ntal position. The weightof the-roof overcomes-the buoyancy of the compartment and gas pressurewithin the tank 'is required to'raise thrroof.

The usual" safety valves and other devices may be providedonthe tank;Guide means mayalso beprovidedto cause the roof t'oino-ve: in a:substantially vertical path only and to prevent ro tation of'the roof.

In the embodiment shown in Fig. 3 thecompartment l8ais provided with aplurality of assages 22 extendihg' through the compartmentme'ar thebottom thereof. These passages are designed to'ventvapor' from th' 'tankwhentheroofrises to "apredetermined height andto prevent raising thebottom of the compartment out of the liquid. There is also shown a driptrough 23 attached-"to the inner surface of. the compartment to'. catchthe condensate forming on the bottom. surface; of the roof 'A pipe: l-llconveys this condensate back into thetankx The trough l'5a is here shownlocated beyond. the shell in 'and supported on brackets 14a. Inthisembodiment there i'swal-so provided a flexible sealing member 25extending from the top outer edge of the trough to the skirt l2. Thissealing member serves to seal the area between the trough and the skirt.

In the embodiment shown in Fig. 4 the sides 15b of the trough slopeoutwardly from the bottom to the top of the trough. This constructionserves to decrease the effect of the receding liquid level as the roofrises because the top of the trough has a larger cross sectional areathan has the bottom.

In the embodiment shown in Fig. 5 the trough is provided with anenlarged section 26 at the top of the trough so as to make thecross-sectional area larger at this point. This construction also servesto decrease the efiect of the receding liquid level as the roof rises.The bottom surface 21 of the enlarged section 25 is preferably locatedbetween the concentric pipes.

3 at substantially th lowest liquid level within the trough when theroof has reached the highest point of its travel.

The embodiment shown in Fig. 6 is similar to the embodiment shown inFig. 2, except that here the trough I3 is provided with a plurality ofsubstantially horizontal downwardly extending pipes 28 also filled withliquid l9a. Each pipe 28 has a smaller pipe 29 located within it withthe smaller pipe attached to the bottom of the compartment I8. Each pairof pipes 28 and 29 is substantially concentric with the outer pipe beingsealed at the bottom as by plate 30. The inner pipe 29 is sealed at theconnection to the compartment, but may be either opened or closed at thebottom. As shown, the inner pipe is closed by a closure plate 3|. Anynumber of these concentric pipes may be placed around the tank. Thesesets of concentric pipes serve to dampen out any tendency for the roofto set up an oscillating up-and-down movement. The dampening is causedby the small area through which the liquid must flow The concentricpipes also serve to prevent any rotational movement of the roof.

.a lifter roof thereover, sealing and leveling means comprising anannular trough of substantial depth at the top of the shell and adaptedto contain a sealing liquid, an annular depending hollow airtightcompartment attached to the roof and extending into the trough wherebythe liquid substantially fills the trough when the roof is in its lowestposition and buoys up the depending compartment which is immersedtherein.

2. The sealing and leveling means of claim 1 wherein the trough islarger in horizontal crosssection at the top than it is at the bottom.

3. The sealing and leveling means of claim 1 .wherein the trough has atleast one side sloping upwardly and outwardly so as to be larger inhori- .zontal cross-section at the top than it is at the bottom.

4. The sealing and leveling means of claim 1 wherein the trough isprovided with substantially parallel sides with one side having its topportion offset to provide a larger cross-section at the top I of thetrough than at the bottom, whereby the liquid level is maintained atsubstantially the bottom of the offset portion when the roof is in itshighest position.

5. The sealing and leveling means of claim 1 wherein the trough isprovided with substantially vertical wells extending downwardly from thebottom thereof, said wells being also adapted to be filled with theliquid and the compartment is provided with downwardly depending hollowfluid-tight posts adapted to telescope in said wells, the innerdimensions of each well being slightly larger than the correspondingouter dimensions of its post.

6. The sealing and leveling means of claim 1 wherein the compartment isprovided with spaced passageways near the bottom thereof extending fromside to side of the compartment.

7. In a lifter roof tank comprising a shell, a lifter roof thereover,and a downwardly-extending skirt attached to the edge of the roof andlocated beyond the shell, sealing and leveling means comprising anannular trough of substantial depth at the top of the shell and adaptedto contain a sealing liquid, an annular depending hollow airtightcompartment attached to the roof and extending into the trough, saidcompartment being adapted to be buoyed up by liquid in the trough whenthe roof is in its lowest position, and a flexible member attached tothe outer side of the trough and pressing against the inner surface ofthe roof skirt, said flexible member extending around substantially theentire circumference of the tank so as to seal the area between theshell and the roof skirt.

8. In a lifter roof tank comprising a shell and a lifter roof thereover,sealing and leveling means comprising an annular trough of substantialdepth at the top of the shell and having sidewalls extending from top tobottom of the trough,

said trough being adapted to contain a sealing liquid, an annulardepending hollow airtight compartment attached to the roof and havingsidewalls extending into the trough whereby the liquid substantiallfills the trough when the roof is in its lowest position and buoys upthe depending compartment which is immersed therein, at least one ofsaid sidewalls being inclined from the vertical.

EDWARD S. FRASER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,061,175 Staber Nov. 17, 19362,3 36 Laird Mar. 14, 1944

